Preparation method of octabromo-ether

Abstract

The invention discloses a preparation method of octabromo-ether, and belongs to the technical field of flame retardants, the preparation method comprises the following steps: synthesizing tetrabromobisphenol A, synthesizing tetrabromobisphenol A diallyl ether, and synthesizing tetrabromobisphenol A bis (2, 3-dibromopropyl) ether; the synthesis of tetrabromobisphenol A diallyl ether comprises the following steps: mixing tetrabromobisphenol A, methanol and a first part of deionized water, heating to 50-55 DEG C, stirring and refluxing until the tetrabromobisphenol A, methanol and the first part of deionized water are completely dissolved, adding sodium hydroxide, stirring and refluxing, adding a catalyst, stirring and refluxing, dropwise adding 3-chloropropene, then continuing stirring and refluxing, distilling out all methanol, and cooling to room temperature to obtain the tetrabromobisphenol A diallyl ether. Mixing with a second part of deionized water and dichloromethane, stirring at room temperature, standing, taking an organic layer, centrifuging, taking supernate, washing with deionized water, distilling out all dichloromethane, and drying; the prepared octabromo-ether is high in purity and yield and good in appearance performance, the condensation problem of the obtained octabromo-ether is avoided, and the yield is stable.

Description

Technical Field

[0001] This invention relates to the field of flame retardant technology, specifically to a method for preparing octabromoether. Background Technology

[0002] Octabromoether, also known as tetrabromobisphenol A-bis(2,3-dibromopropyl) ether, has the molecular formula C0. 21 H 20 Br8O2 is a white, low-toxicity powder, soluble in benzene, acetone, and chloroform, but insoluble in water. It is primarily used as an additive flame retardant in the flame retardation of polyethylene, polypropylene, polybutene, and many polyolefin copolymers. Its molecular structure contains aliphatic and aromatic bromine, resulting in high flame retardant efficiency and the ability to withstand high processing temperatures. It can also be melt-blended with polyethylene, polypropylene, polybutene, and many polyolefin copolymers. Studies have shown that comparing polypropylene flame-retarded with octabromoether with blank polypropylene samples without octabromoether flame retardancy reveals almost no difference in mechanical properties, indicating that octabromoether has virtually no impact on the mechanical properties of polypropylene. Furthermore, the combustion products of octabromoether show almost no detectable presence of the carcinogens polybrominated dibenzodioxane (PBDD) and polybrominated dibenzofuran (PBDF). Therefore, octabromoether possesses advantages such as good flame retardant effect, minimal impact on the mechanical properties of the polymer matrix, and good environmental friendliness, making it one of the main development directions for bromine-based flame retardants with a very broad application prospect.

[0003] Regarding the preparation methods of octabromoether, as published in Yang Chunchang, Tang Xianda, Huang Zhiqing, Shi Guilin, and Yang Xiaojia's "Synthesis of High-Efficiency Flame Retardant - Octabromoether" (Liaoning Chemical Industry, December 1989) and Wu Haiyong's "Research on the Synthesis of Octabromoether" (Suyan Technology, November 2001), the commonly used method for synthesizing octabromoether is to first synthesize tetrabromobisphenol A using bisphenol A as a raw material, then reacting tetrabromobisphenol A with chloropropylene to obtain tetrabromobisphenol A-dienepropyl ether, and finally reacting it with bromine to obtain octabromoether. Meanwhile, the aforementioned literature also optimized the reaction conditions, specifically including the solvent alcohol concentration, the structure of chloropropylene, the mass of tetrabromobisphenol A, and the purification method of octabromoether. Furthermore, regarding the purification method of octabromoether, Wang Yanlin, Wang Fang, and Tang Xinxiuli, in their paper "Research on the Synthesis of Flame Retardant Tetrabromobisphenol A Bis(2,3-Dibromoallyl) Ether," published in *Marine and Lake Salts and Chemicals* in November 2005, further optimized the purification method. The dual-solvent (crystallization solvent / reaction solvent) crystallization separation method yielded the highest production efficiency, with good product purity and appearance, making it an ideal method for industrial production.

[0004] However, the above preparation and purification methods have the following shortcomings: First, the octabromoether synthesized by this method has low thermal stability. As disclosed in Sun Weimin's "New Synthesis Process of High-Purity Tetrabromobisphenol A Bis(2,3-Dibromopropyl) Ether" (Plastic Additives), published in August 2004, the octabromoether synthesized by this method has low thermal stability, with a carbonization temperature of only 260℃ in a test tube. This is because the quality of the tetrabromobisphenol A synthesized in the first step is poor. The article further discloses that the main factors affecting the thermal stability of octabromoether are the purity of the product and the content of free acid. Second, the dual-solvent crystallization separation method requires the use of large amounts of methanol or ethanol. For example, Chinese patent CN100398503C discloses an environmentally friendly method for preparing octabromoether with a high thermal decomposition temperature. This patent discloses that the use of large amounts of low-grade fatty alcohols (mainly methanol or ethanol) during the crystallization precipitation of octabromoether poses a great safety hazard to subsequent centrifugation and drying operations. Moreover, the solvent carried in the octabromoether filter cake evaporates freely without protection during centrifugation, causing environmental pollution.

[0005] The commonly used solutions to the above problems are as follows: First, Sun Weimin. A new process for synthesizing high-purity tetrabromobisphenol A bis(2,3-dibromopropyl) ether. Plastic Additives. In mid-August 2004, it was disclosed that by increasing the purity of the finished octabromoether and increasing the carbonization temperature of octabromoether, the purity of the product is improved by using the surfactant TABS to remove free bromine and impurities during the synthesis of tetrabromobisphenol A; the purity of the product is improved by using the catalyst SB to catalyze the free radical reaction during the synthesis of tetrabromoether; and the carbonization temperature of the finished octabromoether is increased by using surfactant A to reduce the content of free acid in the finished octabromoether during the extraction of octabromoether.

[0006] Second, Chinese patent CN100398503C, "Environmentally Friendly Method for Preparing Octabromoether with High Thermal Decomposition Temperature," discloses a method of dissolving tetrabromobisphenol A dielyl ether in an organic solvent, adding bromine to react, reducing excess bromine with hydrazine hydrate after the reaction, allowing it to stand, washing the lower octabromoether solution with water, adding emulsifiers, additives, seed crystals, and deionized water, and then heating under normal or reduced pressure to remove the solvent. After octabromoether crystallizes, it is separated, washed, and dried. The emulsifiers used are ionic, nonionic, or amphoteric surfactants; the additives are heat stabilizers; and the seed crystals are high-purity octabromoether or other additives with synergistic flame-retardant effects with octabromoether, such as sodium antimonate. This patent obtains octabromoether with a high thermal decomposition temperature by using relevant additives and crystallizing octabromoether without the use of low-grade fatty alcohols.

[0007] However, the above solutions still have the following problems: First, Sun Weimin. A new process for synthesizing high-purity tetrabromobisphenol A bis(2,3-dibromopropyl) ether. Plastic Additives. August 2004. Catalyst SB, as a catalyst for free radical reactions, has the problem of easily remaining in the product during use, which further affects the color of the finished octabromoether. Second, Sun Weimin. A new process for synthesizing high-purity tetrabromobisphenol A bis(2,3-dibromopropyl) ether. Plastic Additives. In mid-August 2004, when preparing tetrabromobisphenol A bis(2,3-dibromopropyl) ether using octabromoether as a raw material, after the reaction was completed, water containing surfactant A was first added, then distilled to recover dichloromethane, and then cooled and crystallized. In the cooling and crystallization, surfactant A can play a role in inhibiting particle aggregation. However, as disclosed in Comparative Example 3 of the environmentally friendly method for preparing octabromoether with high thermal decomposition temperature in Chinese Patent CN100398503C, after cooling and crystallization, it is easy to solidify into a hard block. Third, in the Chinese patent CN100398503C, "Environmentally Friendly Method for Preparing Octabromoether with High Thermal Decomposition Temperature," both seed crystals and emulsifiers are used. Seed crystals promote crystallization, while emulsifiers improve crystal flowability. However, as disclosed in Wang Lei's "Study on Primary Agglomeration Mechanism and Particle Size Control of Crystals—Taking Nicotinic Acid as an Example," a master's thesis from Hebei University of Technology published in May 2021, the particle size and morphology of seed crystals have a significant impact on crystallization, which in turn affects the crystallization rate and the yield of octabromoether. Therefore, when using seed crystals and emulsifiers to promote crystallization, the yield is greatly affected by the particle size and morphology of the seed crystals, leading to unstable yields. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a method for preparing octabromoether, which yields octabromoether with high purity and yield, good appearance, and no condensation problem, and the yield is stable.

[0009] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for preparing octabromoether includes: synthesizing tetrabromobisphenol A, synthesizing tetrabromobisphenol A dielyl ether, and synthesizing tetrabromobisphenol A bis(2,3-dibromopropyl) ether. The synthesis of tetrabromobisphenol A involves mixing bisphenol A, ethanol, deionized water, hydrogen peroxide aqueous solution, and concentrated sulfuric acid, stirring in a cold water bath until completely dissolved, adding bromine dropwise, heating to 45-55°C, stirring and refluxing for 1.5-2 hours, cooling to room temperature to remove excess bromine, adding sodium dodecylbenzenesulfonate, stirring for 15-30 minutes, allowing to stand, taking the organic layer, washing with unsaturated sodium bisulfite aqueous solution, adjusting the pH to 3-4, concentrating under reduced pressure to 20-25% of the original volume, cooling to crystallize, filtering, taking the filter cake, washing with deionized water, and drying to obtain tetrabromobisphenol A. In the synthesis of tetrabromobisphenol A, the ratio of bisphenol A, ethanol, deionized water, hydrogen peroxide aqueous solution, concentrated sulfuric acid, bromine, and sodium dodecylbenzenesulfonate is 114.14g:240-270mL:55-60mL:107-110mL:2-2.5mL:106-115mL:0.016-0.018g. The bromine is added over a period of 4-5 hours. To remove excess bromine, use a saturated sodium bisulfite aqueous solution; When adjusting the pH to 3-4, use an aqueous solution of sodium carbonate. The temperature of the cold water bath is 5-15℃; The ethanol has a mass concentration of 95%; The mass concentration of the hydrogen peroxide aqueous solution is 30%. The concentrated sulfuric acid has a mass concentration of 98%. The mass concentration of the unsaturated sodium bisulfite aqueous solution is 0.2-0.3%; The sodium carbonate aqueous solution has a mass concentration of 10%. The synthesis of tetrabromobisphenol A diallyl ether involves mixing tetrabromobisphenol A, methanol, and a first portion of deionized water, heating the mixture to 50-55°C, stirring and refluxing until completely dissolved, adding sodium hydroxide, stirring and refluxing for 30-50 minutes, adding a catalyst, stirring and refluxing for 20-30 minutes, adding 3-chloropropene dropwise, and continuing to stir and reflux for 4-5 hours. After distilling off all the methanol, the mixture is combined with a second portion of deionized water and dichloromethane, stirred at room temperature for 30-40 minutes, allowed to stand, the organic layer is collected, centrifuged, the supernatant is collected, washed with deionized water, distilled off all the dichloromethane, and dried to obtain tetrabromobisphenol A diallyl ether. In the synthesis of tetrabromobisphenol A dielyl ether, the ratio of tetrabromobisphenol A, methanol, first part of deionized water, sodium hydroxide, catalyst, 3-chloropropene, second part of deionized water, and dichloromethane is 271.94g:400-450mL:140-160mL:44-46g:20-22g:120-140mL:140-160mL:480-520mL; The addition time of the allyl chloride is 1.5-2 hours; The methanol has a mass concentration of 99%. The catalyst is prepared by mixing a first portion of sodium bromide and a first portion of deionized water, heating the mixture to 45-55°C, stirring for 10-20 minutes, adding NaY-type zeolite powder, stirring for 3-4 hours, centrifuging, collecting the precipitate, washing the precipitate with deionized water, drying, mixing with chitosan-acetic acid aqueous solution, heating the mixture to 20-35°C, stirring for 1-2 hours, centrifuging, collecting the precipitate, washing the precipitate with deionized water, drying, then soaking it in glutaraldehyde aqueous solution at room temperature, letting it stand for 8-10 hours, centrifuging, collecting the precipitate, washing the precipitate with deionized water, drying, then mixing with a second portion of sodium bromide and a second portion of deionized water, heating the mixture to 20-35°C, stirring for 3-4 hours, centrifuging, collecting the precipitate, washing the precipitate with deionized water, drying, and obtaining the catalyst. In the preparation of the catalyst, the ratio of the first part sodium bromide, the first part deionized water, NaY type zeolite powder, chitosan acetic acid aqueous solution, glutaraldehyde aqueous solution, the second part sodium bromide, and the second part deionized water is 4.1-4.3g:400-450mL:4-4.5g:180-200mL:180-200mL:40-45g:400-450mL; The particle size of the NaY type zeolite powder is 10 μm; The chitosan-acetic acid aqueous solution contains 1% chitosan and 2% acetic acid by mass. The mass concentration of the glutaraldehyde aqueous solution is 2%; The synthesis of tetrabromobisphenol A bis(2,3-dibromopropyl) ether involves mixing tetrabromobisphenol A dielyl ether and dichloromethane, heating the mixture to 25-30°C, stirring until completely dissolved, adding bromine dropwise, and continuing stirring for 0.5-1 h to remove excess bromine. After standing, the organic layer is collected, washed with deionized water, and seeded deionized water, sodium dodecylbenzenesulfonate, and dodecylphenol polyoxyethylene ether are added. The mixture is stirred at room temperature, and after distilling off all the dichloromethane, it is cooled to crystallize, filtered, and the filter cake is collected, washed with deionized water, and dried to obtain octabromoether. In the synthesis of tetrabromobisphenol A bis(2,3-dibromopropyl) ether, the ratio of tetrabromobisphenol A dielyl ether, dichloromethane, bromine, seeded deionized water, sodium dodecylbenzenesulfonate, and dodecylphenol polyoxyethylene ether is 312g:600-700mL:58-62mL:900-1000mL:0.015-0.017g:0.018-0.02g; The bromine is added over a period of 2-2.5 hours. To remove excess bromine, use a saturated sodium bisulfite aqueous solution; The mass concentration of the seed crystals in the seed-containing deionized water is 1-1.1 g / L; The seed crystals are prepared by grinding octabromoether, sieving it, taking the sieve material, mixing it with hexadecyltrimethylammonium bromide, and then ball milling it to obtain the seed crystals. In the preparation of the seed crystals, the sieve mesh size is 1000 mesh when sieving. The ratio of the sieved material to hexadecyltrimethylammonium bromide is 10g:0.2-0.22g; During ball milling, the ball milling speed is 300-400 rpm, the ball-to-material ratio is 5-8:1, and the ball milling time is 30-40 min. In the preparation of the seed crystals, the liquid phase purity of the octabromoether is 98.9%.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) In the preparation method of the octabromoether of the present invention, the catalyst used in the synthesis of tetrabromobisphenol A diallyl ether is first treated with sodium bromide to improve the adsorption capacity of NaY type zeolite powder, and then treated with chitosan. By utilizing the adsorption force between chitosan and bromide ions, chitosan is bound to the surface of NaY type zeolite powder. After cross-linking the chitosan, the adsorption capacity of the cross-linked chitosan is used to further adsorb more sodium bromide, thereby obtaining a catalyst with high sodium bromide content and large specific surface area. According to the content published by Wu Wenwen, "Research on the process of sodium bromide catalytic synthesis of plastic intermediate bisphenol A diallyl ether. Materials Reports. May 2025", sodium bromide can play a catalytic role in similar reactions. Therefore, by utilizing the catalytic effect of sodium bromide, the reaction yield can be improved and the generation of impurities can be reduced. At the same time, the catalyst can also play the role of adsorbing impurities. (2) The preparation method of the octabromoether of the present invention, in the seed crystal used in the synthesis of tetrabromobisphenol A bis(2,3-dibromopropyl) ether, firstly, the octabromoether is ground to reduce its particle size, then mixed with the cationic surfactant hexadecyltrimethylammonium bromide and ball-milled to coat the surface of the cationic surfactant hexadecyltrimethylammonium bromide, and then, during crystallization, the seed crystal, the anionic surfactant sodium dodecylbenzenesulfonate, and the nonionic surfactant dodecylphenol polyoxyethylene ether are added simultaneously, such as Cao Jian, Zhao Gensuo, Zhang Guobao, Wang Junying, Liu Hongsheng. Anionic-cationic composite surfactant. Research on the application of a fracturing fluid flow aid system. Oilfield Chemistry. September 1992. The content published shows that nonionic surfactants can play a synergistic role in the composite system of cationic and anionic surfactants. Furthermore, it can enhance the inhibitory effect of cationic and anionic surfactants on particle aggregation. At the same time, it can also utilize the interaction between cationic and anionic surfactants to form vesicles on the seed surface, promote crystal formation and reduce the adsorption of impurities, improve the particle size uniformity of the formed octabromoether, and further reduce the influence of seed morphology on yield. (3) The method for preparing octabromoether of the present invention produces octabromoether with high purity and yield, and the octabromoether is white powder. The obtained octabromoether does not have a condensation problem, and the yield is stable between multiple batches. Detailed Implementation

[0011] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention are now described.

[0012] The total molar yield of octabromoether = the molar yield in step 1 (synthesis of tetrabromobisphenol A) × the molar yield in step 2 (synthesis of tetrabromobisphenol A dielyl ether) × the molar yield in step 3 (synthesis of tetrabromobisphenol A bis(2,3-dibromopropyl) ether).

[0013] In calculating the molar yields of step 2 (synthesis of tetrabromobisphenol A dielyl ether) and step 3 (synthesis of tetrabromobisphenol A bis(2,3-dibromopropyl) ether), the liquid phase purity of the raw materials, namely tetrabromobisphenol A and tetrabromobisphenol A dielyl ether, was taken into account.

[0014] Example 1 A method for preparing octabromoether is as follows: 1. Synthesis of Tetrabromobisphenol A: Add 114.14 g of bisphenol A, 240 mL of ethanol, 55 mL of deionized water, 107 mL of hydrogen peroxide solution, and 2 mL of concentrated sulfuric acid to a four-necked flask equipped with a thermometer, dropping funnel, stirrer, condenser, and cold water bath. Turn on the cold water bath and stirrer at 30 rpm until completely dissolved. Add 106 mL of bromine dropwise over 4 hours. Then replace the cold water bath with a heating mantle, turn on the heating mantle, and raise the temperature inside the four-necked flask to 45°C. Stir and reflux for 1.5 hours, then cool to room temperature. Remove excess bisphenol A with a saturated sodium bisulfite solution. Bromine was added to 0.016 g of sodium dodecylbenzenesulfonate, stirred for 15 min, and allowed to stand for 1 h. The organic layer was collected and washed three times with 300 mL of unsaturated sodium bisulfite aqueous solution each time. The pH was adjusted to 3 with sodium carbonate aqueous solution, and the mixture was concentrated under reduced pressure to 20% of its original volume. After cooling and crystallization, the mixture was filtered, and the filter cake was collected and washed three times with 800 mL of deionized water each time. The mixture was then dried at 80 °C to obtain tetrabromobisphenol A. The liquid phase purity of the obtained tetrabromobisphenol A was 99.8%, and a total of 263.15 g of tetrabromobisphenol A was obtained, with a molar yield of 96.58%. The temperature of the cold water bath is 5°C; The ethanol has a mass concentration of 95%; The mass concentration of the hydrogen peroxide aqueous solution is 30%. The concentrated sulfuric acid has a mass concentration of 98%. The mass concentration of the unsaturated sodium bisulfite aqueous solution is 0.2-0.3%; The sodium carbonate aqueous solution has a mass concentration of 10%. 2. Synthesis of tetrabromobisphenol A dielyl ether: Add 271.94 g of tetrabromobisphenol A, 400 mL of methanol, and 140 mL of deionized water to a four-necked flask equipped with a thermometer, dropping funnel, stirrer, condenser, and heating mantle. Turn on the heating mantle and stirrer, raising the temperature inside the flask to 50°C. Control the stirring speed to 30 rpm and stir under reflux until completely dissolved. Add 44 g of sodium hydroxide and stir under reflux for 30 min. Add 20 g of catalyst and stir under reflux for 20 min. Add 120 mL of [catalyst name missing] dropwise. 3-Chloropropene was added dropwise over a period of 1.5 hours, followed by stirring and reflux for 4 hours. After distilling off all methanol, the mixture was combined with 140 mL of deionized water and 480 mL of dichloromethane. The mixture was stirred at room temperature for 30 minutes, allowed to stand for 1 hour, and the organic layer was collected. The layer was centrifuged, and the supernatant was washed three times with 1800 mL of deionized water each time. After distilling off all dichloromethane, the mixture was dried at 80 °C to obtain tetrabromobisphenol A diallyl ether. The liquid phase purity of the obtained tetrabromobisphenol A diallyl ether was 99.7%, and a total of 307.09 g of tetrabromobisphenol A diallyl ether was obtained, with a molar yield of 98.33%. The methanol has a mass concentration of 99%. The catalyst is prepared as follows: 4.1 g of sodium bromide and 400 mL of deionized water are added to a four-necked flask equipped with a thermometer, stirrer, and heating mantle. The heating mantle and stirrer are turned on, and the temperature inside the flask is raised to 45°C. The stirring speed is controlled at 60 rpm, and the mixture is stirred for 10 min. 4 g of NaY-type zeolite powder is added, and the mixture is stirred for 3 h. After centrifugation, the precipitate is collected and washed three times with deionized water, using 40 mL each time. The precipitate is dried at 80°C and then added to a four-necked flask equipped with a thermometer, stirrer, and heating mantle. 180 mL of chitosan-acetic acid aqueous solution is added, and the heating mantle and stirrer are turned on, and the temperature inside the flask is raised to 20°C. The stirring speed is controlled at 60 rpm, and the mixture is stirred for 1 h. After centrifugation, the precipitate is collected and washed three times with deionized water, using 40 mL each time. The precipitate is dried at 80°C and then soaked at room temperature in 1... The precipitate was placed in 80 mL of glutaraldehyde aqueous solution, allowed to stand for 8 hours, centrifuged, and washed three times with deionized water, each time using 40 mL. It was then dried at 80 °C and added to a four-necked flask equipped with a thermometer, stirrer, and heating mantle. 40 g of sodium bromide and 400 mL of deionized water were added. The heating mantle and stirrer were turned on, and the temperature inside the four-necked flask was raised to 20 °C. The stirring speed of the stirrer was controlled at 60 rpm, and the mixture was stirred for 3 hours. After centrifugation, the precipitate was collected and washed three times with deionized water, each time using 40 mL. It was then dried at 80 °C to obtain the catalyst. The particle size of the NaY type zeolite powder is 10 μm; The chitosan-acetic acid aqueous solution contains 1% chitosan and 2% acetic acid by mass. The mass concentration of the glutaraldehyde aqueous solution is 2%; 3. Synthesis of tetrabromobisphenol A bis(2,3-dibromopropyl) ether: Add 312 g of tetrabromobisphenol A dielyl ether and 600 mL of dichloromethane to a four-necked flask equipped with a thermometer, dropping funnel, stirrer, condenser, and heating mantle. Turn on the heating mantle and stirrer, raising the temperature inside the flask to 25°C. Control the stirring speed to 30 rpm and stir until completely dissolved. Add 58 mL of bromine dropwise over 2 hours, then continue stirring for 0.5 hours. Remove excess bromine with a saturated sodium bisulfite aqueous solution. Let stand for 1 hour, collect the organic layer, and use a deionization agent... The sample was washed once with 1500 mL of deionized water, and 900 mL of seeded deionized water, 0.015 g of sodium dodecylbenzenesulfonate, and 0.018 g of dodecylphenol polyoxyethylene ether were added. The mixture was stirred at room temperature for 20 min. After distilling off all the dichloromethane, the sample was cooled to crystallize, filtered, and the filter cake was collected. The filter cake was washed three times with 1800 mL of deionized water each time and dried at 80 °C to obtain octabromoether. The liquid phase purity of the obtained octabromoether was 98.6%. A total of 450.18 g of tetrabromobisphenol A dielyl ether was obtained, with a molar yield of 94.36%. The mass concentration of the seed crystals in the seed-containing deionized water is 1 g / L; The method for preparing the seed crystal is as follows: after grinding octabromoether, it is passed through a 1000-mesh sieve. 10g of the sieve material is taken and mixed with 0.2g of hexadecyltrimethylammonium bromide and then ball-milled. The ball milling speed is controlled at 300rpm and the ball-to-material ratio is controlled at 5:1. The ball milling is carried out for 30min to obtain the seed crystal. In the preparation of the seed crystals, the liquid phase purity of the octabromoether is 98.9%.

[0015] The total molar yield in this embodiment is 89.61%.

[0016] Example 2 A method for preparing octabromoether is as follows: 1. Synthesis of Tetrabromobisphenol A: Add 114.14 g of bisphenol A, 270 mL of ethanol, 60 mL of deionized water, 110 mL of hydrogen peroxide solution, and 2.5 mL of concentrated sulfuric acid to a four-necked flask equipped with a thermometer, dropping funnel, stirrer, condenser, and cold water bath. Turn on the cold water bath and stir at 60 rpm until completely dissolved. Add 115 mL of bromine dropwise over 5 hours. Then replace the cold water bath with a heating mantle, turn on the heating mantle, and raise the temperature inside the four-necked flask to 55°C. Stir and reflux for 2 hours, then cool to room temperature. Remove excess bisphenol A with a saturated sodium bisulfite solution. Bromine was added to 0.018 g of sodium dodecylbenzenesulfonate, stirred for 30 min, and allowed to stand for 2 h. The organic layer was collected and washed 5 times with 400 mL of unsaturated sodium bisulfite aqueous solution each time. The pH was adjusted to 4 with sodium carbonate aqueous solution, and the mixture was concentrated under reduced pressure to 25% of its original volume. After cooling and crystallization, the mixture was filtered, and the filter cake was collected and washed 5 times with 1000 mL of deionized water each time. The mixture was then dried at 85 °C to obtain tetrabromobisphenol A. The liquid phase purity of the obtained tetrabromobisphenol A was 99.9%, and a total of 265.71 g of tetrabromobisphenol A was obtained, with a molar yield of 97.61%. The temperature of the cold water bath is 15°C; The ethanol has a mass concentration of 95%; The mass concentration of the hydrogen peroxide aqueous solution is 30%. The concentrated sulfuric acid has a mass concentration of 98%. The mass concentration of the unsaturated sodium bisulfite aqueous solution is 0.3%; The sodium carbonate aqueous solution has a mass concentration of 10%. 2. Synthesis of tetrabromobisphenol A dielyl ether: Add 271.94 g of tetrabromobisphenol A, 450 mL of methanol, and 160 mL of deionized water to a four-necked flask equipped with a thermometer, dropping funnel, stirrer, condenser, and heating mantle. Turn on the heating mantle and stirrer, raising the temperature inside the flask to 55°C. Control the stirring speed to 60 rpm and stir under reflux until completely dissolved. Add 46 g of sodium hydroxide and stir under reflux for 50 min. Add 22 g of catalyst and stir under reflux for 30 min. Add 140 mL of [catalyst name missing] dropwise. 3-Chloropropene was added dropwise over a period of 2 hours, followed by stirring and reflux for 5 hours. After distilling off all methanol, the mixture was combined with 160 mL of deionized water and 520 mL of dichloromethane. The mixture was stirred at room temperature for 40 minutes, allowed to stand for 2 hours, and the organic layer was collected. The mixture was centrifuged, and the supernatant was washed five times with 2200 mL of deionized water each time. After distilling off all dichloromethane, the mixture was dried at 85°C to obtain tetrabromobisphenol A diallyl ether. The liquid phase purity of the obtained tetrabromobisphenol A diallyl ether was 99.8%, and a total of 308.42 g of tetrabromobisphenol A diallyl ether was obtained, with a molar yield of 98.75%. The methanol has a mass concentration of 99%. The catalyst is prepared as follows: 4.3 g of sodium bromide and 450 mL of deionized water are added to a four-necked flask equipped with a thermometer, stirrer, and heating mantle. The heating mantle and stirrer are turned on, and the temperature inside the flask is raised to 55°C. The stirring speed is controlled at 120 rpm, and the mixture is stirred for 20 min. 4.5 g of NaY-type zeolite powder is added, and the mixture is stirred for 4 h. After centrifugation, the precipitate is collected and washed five times with deionized water, using 50 mL each time. The precipitate is dried at 85°C and then added to a four-necked flask equipped with a thermometer, stirrer, and heating mantle. 200 mL of chitosan-acetic acid aqueous solution is added, and the heating mantle and stirrer are turned on, and the temperature inside the flask is raised to 35°C. The stirring speed is controlled at 120 rpm, and the mixture is stirred for 2 h. After centrifugation, the precipitate is collected and washed five times with deionized water, using 50 mL each time. The precipitate is dried at 85°C and then soaked at room temperature in 20 mL of water. The precipitate was placed in 0 mL of glutaraldehyde aqueous solution, allowed to stand for 10 h, centrifuged, and the precipitate was taken. The precipitate was washed 5 times with deionized water, each time using 50 mL. The precipitate was dried at 85 °C and then added to a four-necked flask equipped with a thermometer, a stirrer, and a heating mantle. 45 g of sodium bromide and 450 mL of deionized water were added. The heating mantle and the stirrer were turned on, and the temperature inside the four-necked flask was raised to 35 °C. The stirring speed of the stirrer was controlled at 120 rpm and stirred for 4 h. The precipitate was centrifuged, and the precipitate was taken. The precipitate was washed 5 times with deionized water, each time using 50 mL. The precipitate was dried at 85 °C to obtain the catalyst. The particle size of the NaY type zeolite powder is 10 μm; The chitosan-acetic acid aqueous solution contains 1% chitosan and 2% acetic acid by mass. The mass concentration of the glutaraldehyde aqueous solution is 2%; 3. Synthesis of tetrabromobisphenol A bis(2,3-dibromopropyl) ether: Add 312 g of tetrabromobisphenol A dielyl ether and 700 mL of dichloromethane to a four-necked flask equipped with a thermometer, dropping funnel, stirrer, condenser, and heating mantle. Turn on the heating mantle and stirrer to raise the temperature inside the flask to 30°C. Control the stirring speed of the stirrer to 60 rpm and stir until completely dissolved. Add 62 mL of bromine dropwise over a period of 2.5 h, then continue stirring for 1 h. Remove excess bromine with a saturated sodium bisulfite aqueous solution. Let stand for 2 h, collect the organic layer, and use a deionization agent... The sample was washed twice with 2000 mL of deionized water each time. Then, 1000 mL of seeded deionized water, 0.017 g of sodium dodecylbenzenesulfonate, and 0.02 g of dodecylphenol polyoxyethylene ether were added. The mixture was stirred at room temperature for 30 min. After distilling off all the dichloromethane, the sample was cooled to crystallize, filtered, and the filter cake was collected. The filter cake was washed five times with 2200 mL of deionized water each time and dried at 85 °C to obtain octabromoether. The liquid phase purity of the obtained octabromoether was 98.4%. A total of 452.37 g of tetrabromobisphenol A dielyl ether was obtained, with a molar yield of 94.54%. The mass concentration of the seed crystals in the seed-containing deionized water is 1.1 g / L; The method for preparing the seed crystal is as follows: after grinding octabromoether, it is passed through a 1000-mesh sieve. 10g of the sieve material is taken and mixed with 0.22g of hexadecyltrimethylammonium bromide and then ball-milled. The ball milling speed is controlled at 400rpm and the ball-to-material ratio is controlled at 8:1. The ball milling is carried out for 40min to obtain the seed crystal. In the preparation of the seed crystals, the liquid phase purity of the octabromoether is 98.9%.

[0017] The total molar yield in this embodiment is 91.13%.

[0018] Comparative Example 1 Except for the step of synthesizing tetrabromobisphenol A dielyl ether in step 2, which does not use a catalyst, everything else is exactly the same as in Example 1.

[0019] The liquid phase purity of the tetrabromobisphenol A diallyl ether obtained in step 2 was 99.5%, and a total of 292.59 g of tetrabromobisphenol A diallyl ether was obtained, with a molar yield of 93.50%. The total molar yield in this comparative example was 85.02%.

[0020] Comparative Example 2 Except for the preparation method of the catalyst used in step 2, which is the same as in Example 1, everything else is exactly the same.

[0021] The catalyst preparation method in this comparative example is as follows: Add 4.1g of sodium bromide and 400mL of deionized water to a four-necked flask equipped with a thermometer, a stirrer, and a heating mantle. Turn on the heating mantle and the stirrer, and raise the temperature inside the four-necked flask to 45℃. Control the stirring speed of the stirrer to 60rpm and stir for 10min. Add 4g of NaY type zeolite powder and stir for 3h. Centrifuge, collect the precipitate, wash the precipitate three times with deionized water, each time using 40mL, and dry at 80℃ to obtain the catalyst. The NaY-type zeolite powder has a particle size of 10 μm.

[0022] The liquid phase purity of the tetrabromobisphenol A diallyl ether obtained in step 2 was 99.6%, and a total of 296.85 g of tetrabromobisphenol A diallyl ether was obtained, with a molar yield of 94.95%. The total molar yield in this comparative example was 86.40%.

[0023] Comparative Example 3 Except for the step of synthesizing tetrabromobisphenol A bis(2,3-dibromopropyl) ether in step 3, which does not use seed crystals, everything else is exactly the same as in Example 1.

[0024] The octabromoether obtained in step 3 had a liquid phase purity of 97.5%, and a total of 427.44 g of tetrabromobisphenol A dielyl ether was obtained, with a molar yield of 88.60%. The total molar yield in this comparative example was 84.13%.

[0025] Comparative Example 4 Except for the method of preparing the seed crystals used in step 3, which is different from that in the synthesis of tetrabromobisphenol A bis(2,3-dibromopropyl) ether, everything else is exactly the same as in Example 1.

[0026] The octabromoether obtained in step 3 had a liquid phase purity of 97.1%, and a total of 448.03 g of tetrabromobisphenol A dielyl ether was obtained, with a molar yield of 92.48%. The total molar yield in this comparative example was 87.82%.

[0027] Test Example 1 The appearance of the octabromoethers obtained in Examples 1-2 and Comparative Examples 1-4 was observed and recorded, and the results are as follows:

[0028] Test Example 2 Ten batches of octabromoether were prepared consecutively according to the preparation methods of Examples 1-2 and Comparative Examples 1-4. The purity and total molar yield of the ten batches of octabromoether were statistically analyzed. The differences between the maximum and minimum purity, and the differences between the maximum and minimum total molar yield were calculated. The appearance of the ten batches of octabromoether was also observed and analyzed, and the number of batches with particle size inhomogeneity was counted. The results are as follows:

[0029] The results of Examples 1-2, Comparative Examples 1-4, and Test Examples 1-2 show that, compared with Example 1, Comparative Examples 1-2 all have the problem of low total molar yield of the prepared octabromoether; Comparative Examples 3-4 all have the problems of low purity and total molar yield of the prepared octabromoether, uneven particle size distribution, and large differences in purity and total molar yield between batches.

Claims

1. A method for preparing octabromoether, characterized in that, include: Synthesize tetrabromobisphenol A, synthesize tetrabromobisphenol A dielyl ether, synthesize tetrabromobisphenol A bis(2,3-dibromopropyl) ether; The synthesis of tetrabromobisphenol A diallyl ether involves mixing tetrabromobisphenol A, methanol, and a first portion of deionized water, heating the mixture to 50-55°C, stirring and refluxing until completely dissolved, adding sodium hydroxide, stirring and refluxing for 30-50 minutes, adding a catalyst, stirring and refluxing for 20-30 minutes, adding 3-chloropropene dropwise, and continuing to stir and reflux for 4-5 hours. After distilling off all the methanol, the mixture is combined with a second portion of deionized water and dichloromethane, stirred at room temperature for 30-40 minutes, allowed to stand, the organic layer is collected, centrifuged, the supernatant is collected, washed with deionized water, distilled off all the dichloromethane, and dried to obtain tetrabromobisphenol A diallyl ether. The synthesis of tetrabromobisphenol A bis(2,3-dibromopropyl) ether involves mixing tetrabromobisphenol A dielyl ether and dichloromethane, heating the mixture to 25-30°C, stirring until completely dissolved, adding bromine dropwise, and continuing stirring for 0.5-1 h to remove excess bromine. After standing, the organic layer is collected, washed with deionized water, and seeded deionized water, sodium dodecylbenzenesulfonate, and dodecylphenol polyoxyethylene ether are added. The mixture is stirred at room temperature, and after distilling off all the dichloromethane, it is cooled to crystallize, filtered, and the filter cake is collected, washed with deionized water, and dried to obtain octabromoether.

2. The method for preparing octabromoether according to claim 1, characterized in that, The synthesis of tetrabromobisphenol A involves mixing bisphenol A, ethanol, deionized water, hydrogen peroxide aqueous solution, and concentrated sulfuric acid, stirring in a cold water bath until completely dissolved, adding bromine dropwise, heating to 45-55°C, stirring and refluxing for 1.5-2 hours, cooling to room temperature to remove excess bromine, adding sodium dodecylbenzenesulfonate, stirring for 15-30 minutes, allowing to stand, taking the organic layer, washing with unsaturated sodium bisulfite aqueous solution, adjusting the pH to 3-4, concentrating under reduced pressure to 20-25% of the original volume, cooling to crystallize, filtering, taking the filter cake, washing with deionized water, and drying to obtain tetrabromobisphenol A.

3. The method for preparing octabromoether according to claim 2, characterized in that, In the synthesis of tetrabromobisphenol A, the ratio of bisphenol A, ethanol, deionized water, hydrogen peroxide aqueous solution, concentrated sulfuric acid, bromine, and sodium dodecylbenzenesulfonate is 114.14g:240-270mL:55-60mL:107-110mL:2-2.5mL:106-115mL:0.016-0.018g.

4. The method for preparing octabromoether according to claim 2, characterized in that, In the synthesis of tetrabromobisphenol A, the bromine is added over a period of 4-5 hours. To remove excess bromine, use a saturated sodium bisulfite aqueous solution; When adjusting the pH to 3-4, use an aqueous solution of sodium carbonate. The temperature of the cold water bath is 5-15℃; The ethanol has a mass concentration of 95%; The mass concentration of the hydrogen peroxide aqueous solution is 30%. The concentrated sulfuric acid has a mass concentration of 98%. The mass concentration of the unsaturated sodium bisulfite aqueous solution is 0.2-0.3%; The sodium carbonate aqueous solution has a mass concentration of 10%.

5. The method for preparing octabromoether according to claim 1, characterized in that, In the synthesis of tetrabromobisphenol A dielyl ether, the ratio of tetrabromobisphenol A, methanol, first part of deionized water, sodium hydroxide, catalyst, 3-chloropropene, second part of deionized water, and dichloromethane is 271.94g:400-450mL:140-160mL:44-46g:20-22g:120-140mL:140-160mL:480-520mL.

6. The method for preparing octabromoether according to claim 1, characterized in that, In the synthesis of tetrabromobisphenol A dielyl ether, the allyl chloride is added dropwise over a period of 1.5-2 hours. The methanol has a mass concentration of 99%.

7. The method for preparing octabromoether according to claim 1, characterized in that, The catalyst is prepared by mixing a first portion of sodium bromide and a first portion of deionized water, heating the mixture to 45-55°C, stirring for 10-20 minutes, adding NaY-type zeolite powder, stirring for 3-4 hours, centrifuging, collecting the precipitate, washing the precipitate with deionized water, drying it, mixing it with a chitosan-acetic acid aqueous solution, heating the mixture to 20-35°C, stirring for 1-2 hours, centrifuging, collecting the precipitate, washing the precipitate with deionized water, drying it, then soaking it in a glutaraldehyde aqueous solution at room temperature, letting it stand for 8-10 hours, centrifuging, collecting the precipitate, washing the precipitate with deionized water, drying it, then mixing it with a second portion of sodium bromide and a second portion of deionized water, heating the mixture to 20-35°C, stirring for 3-4 hours, centrifuging, collecting the precipitate, washing the precipitate with deionized water, drying it, and obtaining the catalyst.

8. The method for preparing octabromoether according to claim 7, characterized in that, In the preparation of the catalyst, the ratio of the first part sodium bromide, the first part deionized water, NaY type zeolite powder, chitosan acetic acid aqueous solution, glutaraldehyde aqueous solution, the second part sodium bromide, and the second part deionized water is 4.1-4.3g:400-450mL:4-4.5g:180-200mL:180-200mL:40-45g:400-450mL; The particle size of the NaY type zeolite powder is 10 μm; The chitosan-acetic acid aqueous solution contains 1% chitosan and 2% acetic acid by mass. The mass concentration of the glutaraldehyde aqueous solution is 2%.

9. The method for preparing octabromoether according to claim 1, characterized in that, In the synthesis of tetrabromobisphenol A bis(2,3-dibromopropyl) ether, the ratio of tetrabromobisphenol A dielyl ether, dichloromethane, bromine, seeded deionized water, sodium dodecylbenzenesulfonate, and dodecylphenol polyoxyethylene ether is 312g:600-700mL:58-62mL:900-1000mL:0.015-0.017g:0.018-0.02g; The bromine is added over a period of 2-2.5 hours. To remove excess bromine, use a saturated sodium bisulfite aqueous solution; The mass concentration of the seed crystals in the seed-containing deionized water is 1-1.1 g / L.

10. The method for preparing octabromoether according to claim 1, characterized in that, The seed crystals are prepared by grinding octabromoether, sieving it, taking the sieve material, mixing it with hexadecyltrimethylammonium bromide, and then ball milling it to obtain the seed crystals. In the preparation of the seed crystals, the sieve mesh size is 1000 mesh when sieving. The ratio of the sieve residue to hexadecyltrimethylammonium bromide is 10g:0.2-0.22g; During ball milling, the ball milling speed is 300-400 rpm, the ball-to-material ratio is 5-8:1, and the ball milling time is 30-40 min. In the preparation of the seed crystals, the liquid phase purity of the octabromoether is 98.9%.

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